Fuelling systems of the mentioned type must, if they are used for fuelling of aircraft, meet substantially two primary requirements. The first primary requirement is that the fuelling arm can be extended to a sufficient length, so that fuelling of both very large aircraft and aircrafts which are not exactly parked at the parking position is possible. The other requirement is that the fuelling system, during nonuse, must be able to be stored as space-savingly and operatively safe as possible and yet be protected against outside influences.
It has proven to be disadvantageous in known fuelling systems to cause the individual pipe elements of the fuelling arm to be relatively bulky since they can often be connected to the aircraft only with a considerable amount of work. Furthermore, to make the movability of the fuelling arm easier, undercarriages are often used, on which at least parts of the fuelling arm are supported in order to facilitate a pulling or pushing of the undercarriages to and from the aircraft. All this has the result that the fuelling arm, in an inoperative state, can hardly be collapsed or is at least difficult to collapse, so that it can be stored space-savingly. All of these movable systems in addition have the disadvantage that they must be transported to the edge of the hydrant surface when not in operation. In the case of the fuelling arm known from the above-mentioned patent, it has proven to be disadvantageous for the fuelling arm to be lowered and to be only of a relatively short length, which is not sufficient for many purposes.
A further disadvantage of both of these just mentioned and also other fuelling arms is that these are not sufficiently elevationally adjustable in order to connect a fuelling coupling mounted on the free end of the fuelling arm to the tank connection of various aircraft.
The basic purpose of the invention is to provide a raisable and lowerable fuelling system of the above-mentioned type which, with a simple design and easy operation, secures a large fuelling range and can be stored space-savingly during nonuse and can be lowered into the ground through a comparatively small, closable opening, which can be covered with a heavy-load bearing cover over which travel can take place.
The purpose is attained according to the invention by a lifting and lowering device including a plate liftable to a position flush with respect to the ground, on which plate is supported a first joint pivotal about a vertical axis, by the respectively adjoining pipe elements being arranged each substantially horizontally, being angled at their ends and being connected with one another each by at least one vertical joint, and by the dimension of the plate equalling at least the length of the longest pipe element.
The inventive fuelling system is characterized by a number of significant advantages. Since the fuelling arm or rather its pipe elements are dimensioned such that the fuelling arm can be arranged, in an inoperative state, completely above the plate, it is possible to lower the entire fuelling arm including the plate into a vertically opening enclosed space or shaft in an airport apron. Thus, the entire apron of the aircraft is kept clear during nonuse, so that the aircraft can roll unhindered and that the servicing personnel and the operators are not hindered by the fuelling system. A further significant advantage of the inventive fuelling system is that same does not present a danger for an accident in the inoperative state, so that no measures need to be taken to prevent a collision with the fuelling system. This is of a particular advantage during poor visibility or heavy traffic on an apron or the runways. Furthermore, it has proven to be advantageous that the fuelling system can be received completely in the vertically enclosed space during the inoperative state and thus occurring fuel residues or vapors can be absorbed without burdening the environment.
In the operative state in which the plate is lifted to ground level of the apron or of the runway, there also does not exist the danger that persons will fall into the open shaft. This is particularly important when the fuelling arm is pivoted to assume its fuelling position. In particular during pivoting of the first pipe arm, there exists in the case of the known fuelling arms arranged in a substantially open shaft the danger that an operator will fall into the shaft.
A particularly favorable further development of the invention provides that at least one of the pipe elements is supported by a support wheel. The support wheel can be used to support a portion of the fuelling arm, however, it does not hinder the free unfolding capability of the fuelling arm or rather of its arrangement on the plate and the lowering of the fuelling arm together with the plate during nonuse.
In order to facilitate the collapsing of the fuelling arm when the fuelling arm is very long and a plurality of individual pipe elements exist, there is provided, according to the invention, a first and a third pipe element arranged at the same level and a second pipe element and a fourth pipe element arranged at different levels with respect to the first and the third pipe elements. The first and the third pipe elements can be arranged substantially parallel or side-by-side on the plate, while the second and the fourth pipe elements must be arranged in an inclined position above the first and the third pipe elements. This makes it possible to arrange the pipe elements in the smallest space. It has proven to be advantageous in this described embodiment when the third pipe element is supported by means of a support wheel. Since this pipe element, in relationship to the other pipe elements, is the lowest one, it can be supported by means of the support wheel without the pivotability of the remaining pipe elements and their collapsibility above the plate being hindered.
In order to assure that there is a capability to adjust the height of the inventive fuelling arm, at least one pipe element can be pivoted about a horizontal joint arranged transversely with respect to the longitudinal axis of the pipe element. The second pipe element is constructed such that it is pivotal on both sides each about a horizontal axis.
To permit, in the case of the inventively possible great length of the fuelling arm, an easier elevational adjustability of the free end area, there is provided, according to the invention, an elevation-adjusting device on the support wheel on the third pipe element.
The pipe element lying between the first and the third pipe elements, which is connected through horizontally lying joints directly thereto, forms with a guide rod which interconnects the first and third pipe sections, a parallelogram. This parallelogram assures that the two vertical joints, which are connected thereafter, always lie vertically also during an elevational adjustment. The advantage is that the fuelling coupling is always pivotal about a vertical joint and thus an undesired changing to the lowermost point cannot occur. Furthermore, it is possible to reduce the number of support wheels.
The pipe elements arranged after the fourth pipe element are preferably pivotal alternately about horizontal or rather vertical joints, each offset at 90.degree. to one another, and are arranged above the first to fourth pipe elements. Since the shaft into which the fuelling arm is to be lowered can be sufficiently deep, the total height of the fuelling arm collapsed during nonuse is not so important. Of decisive importance is rather the surface area of the fuelling arm needed in the collapsed state.
The recess for the plate can be covered in a preferred manner by a weight-balanced lid over which, in the closed state, also heavy aircraft can travel and which can easily be opened or closed by one operator.
In order to assure a free lifting and lowering of the plate, it is particularly advantageous when the supply line is connected to a connecting pipe element bent at its ends through a joint pivotal about a horizontal axis. The free end of the connecting pipe element is connected to a further joint pivotal about a horizontal axis, which joint in turn is connected through an intermediate pipe section to the first joint pivotal about the vertical axis. This development results in a scissorlike pipe connection which does not offer much resistance to a vertical movement of the plate.